Electron-emission device



Dec. 27, 1927. 1,654,513

H. J. ROUND ELECTRON EMISSION DEVICE Filed Sept. 2, 1920 5mm jfellry Josqob Kat/0d Patented Dec. 27, 1927. v

UNITED STATES 1,654,513 PATENT OFFICE.

HENRY JOSEPH ROUND, LONDON, ENGLAND, ASSIGNOR TO RADIO CORPORATION OF AMERICA, 01' NEW YORK, N. Y., A CORPORATION OF DELAWARE. I

ELECTRON-EMISSION DEVICE.

Application filed September 2, 1920, Serial No. 407,664, and in Great Britain September 8, 1919.

When a valve is employed for transmitting in wireless signaling, one end of the filament is connected through a circuit to the anode and in consequence when the power is such 1 5 that the electronic emission current is comparable with the current employed for heating the filament the latter is unevenly heated owing to the fact that the emission current varies at difierent points of the filament.

According to this invention and in order to reduce the unevenness of the heating I connect to the filament at a number of points evenly spaced along it a number of resistances, the other ends of which are connected together and form the cathode terminal. These resistances must be sufiiciently large to prevent portions of the filament being short circuited. By employing a large 'number of resistances the emission current may be divided approximately uniformly between the resistances and the heating of the filament may thus be made much more uniform.

The resistances and their common junction are preferably placed inside the valve so that only one additional seal is necessary.

My invention is illustrated by the accompanying diagram which shows a zig zag filament A having resistances B connected to it at various points, their other ends being connected to a lead 0 the middle point of which is connected through the usual form of circuit to the anode D.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, what Iclaim is 1. In combination, a thermionic valve having filament and anode electrodes adapted to carry space currents, a circuit connected 4o therebetween, a direct current source of heating current for the filament and a pair of resistances connected in said circuit for carrying the space currents to the filament, each having one end connected to a different point of the filament and their other ends connected to the said circuit.

2. In combination, a thermionic valve having filament and anode electrodes arranged to carry space currents in a circuit therebetween, a source of direct current connected to the filament for heating it and a pair of resistances connected in said circuit for carrying the space current to the filament, said resistances having a common point of connection and the other ends of each being and to said source.

resistances connected in said circuit for carrying the current to the filament, said resistances havin a common point of connection and the 05181 ends of each being connected to different points of the filament and to said source, and a source of space current connected between said common point and said anode.

4. In combination, a thermionic valve having filament and anode electrodes arranged to carry space current in a circuit therebetween, a source of direct current for heating said filament, a resistance connected to an intermediate point of said filament and a source of current having one terminal connected to said anode and the other terminal connected to both ends of the filament and also to said intermediate point through said resistance.

5. A thermionic valve comprising an enclosure, a filament and an anode, arranged to carry siplace current therebetween, a source of anode lament current and a plurality of resistances in said enclosure, adapted to be connected to the. source of anode filament current, said resistances being connected to difierent points'of the filament for carrying space current thereto.

6. A thermionic valve comprising an enclosure having a filament, an anode and a plurality of resistances therein connected to different points of the filament for distributing the anode-filament space current along the filament.

7. In a thermionic valve, the combination with a filament and an anode for said valve of a resistance means within the valve for distributing the anode filament space current 100 along the filament.

8. In a themionic valve, the combination with a filament and an anode for said valve of three or more resistances and means connecting together one end of each resistance, 1 the other ends of the resistances being connected to different points on the filament.

9. In a thermionic valve, in combination,

a filament and an anode for said valve, three or more resistances and means connecting to- 110 uated envelope within which the aforesaid.

elements are mounted.

10. In a thermionic valve, a combination with a filament and an anode for said valve mounted in an enclosure of three or more resistances, a lead connecting together one end of each resistance and mounted in the enclosure, the other ends of the resistances being connected to different points of the filament.

11. In a thermionic valve, the combination II with a filament and an anode for said valve -of three or more resistances of equal value and means connecting together one end of each resistance, the other ends of the resistances being connected to different points on i the filament.

12-. In a thermionic valve, in combination, a filament and an anode for sa1d valve, three or more resistances of substantially equal HENRY JOSEPH ROUND. 

